Abrasive cleaning composition



United States Patent Oil 3,942,622 Patented July 3, 1962 3,042,622ABRASIVE CLEANING COMPOSITION Hans George Kirschenbauer, Allendale,N..l., assignor to Colgate-Palmolive Company, New York, N.Y., acorporation of Delaware No Drawing. Filed Nov. 1, 1957, Ser. No. 693,80316 Claims. (Cl. 25299) The present invention relates to an abrasivecleaning composition exhibiting alkaline and acidic pH conditions in apredetermined order of succession in water, and to a process forpreparing the same.

Scouring powders and similar abrasive compositions are well-known in theart. Such cleansers may contain alkaline inorganic salts for certaincleansing effects, particularly for grease removal. Cleaningcompositions containing abrasive material and an acidic ingredient toobtain more effective removal of stains from metal surfaces have beenproposed also. Heretofore, abrasive preparations containing both acidicand alkaline ingredients have not been made as articles of commerce. Itwould appear that the presence of both acidic and alkaline ingredientsin one composition would result in a tendency of these materials toneutralize one another upon admixture with water such that separate anddistinct alkaline and acidic cleansing properties would not be obtainedthereby.

In accordance with the present invention, it has been discovered thatthere can be prepared an abrasive cleansing composition comprisingessentially a mixture of a waterinsoluble abrasive material, and analkaline ingredient and an acidic ingredient, said composition exertingboth alkaline and acidic cleansing properties in water in any desiredorder. More particularly, the present invention relates to an abrasivecleaning composition which upon admixture with water is adapted to yieldan alkaline pH condition and an acidic pH condition to the resultingcleaning solution in a predetermined order of succession which comprisesessentially a mixture of a Water-insoluble abrasive material, awater-soluble alkaline ingredient which upon contact with water rendersthe solution alkaline, a water-soluble acidic ingredient which uponcontact with water renders the solution acidic, one of the two latteringredients dissolving sufliciently upon admixture of said compositionwith water so that the resulting cleansing solution initially has eitheran alkaline or acidic condition and the other ingredient being adaptedto dissolve in an amount sufiicient to subsequently convert saidcleansing solution to the opposite pI-I condition. A preferredembodiment relates to a scouring cleanser containing a major proportionof a water-insoluble siliceous abrasive, and minor proportions of awater-soluble alkaline builder salt and a normally solid water-solubleacid, said acid having a coating of a water-dispersible material toretard the rate of solubility of said acid. Various other preferredembodiments will be apparent in the following description.

For convenience of illustration, the invention will be describedparticularly with respect to the composition yielding successivealkaline and acidic pH conditions though it is to be understood thatcompositions exhibiting the inverse order are within the scope of theinvention. Where reference is made to either an alkaline or acidic pHcondition in the specification and claims, it is intended that suchcondition be illustrated by a 20% slurry of the composition in water.

The ingredient which produces the abrasivecharacteristics primarily is awater-insoluble abrasive'material in particulate form. These abrasiveagents suitable for use in scouring powders and the like are well-knownin the art and are generally siliceous materials. Y Suitable examplesare silex, tripoli, pumice, volcanic ash, pumicite, bentonite,diatom-aceous earth, feldspar, etc. and'mixtures thereof. The abrasivemay vary in hardness and particle size as desired with the mesh size ofthe particles varying from about 40 to about 400 generally, andpreferably being not larger than 100 mesh, as determined on a US.standard sieve. The amount of the abrasive is variable but is usually amajor proportion of the total solids (e.g. at least about and preferablyabout 60 to about 98% by weight. Any water-soluble ingredient whichyields an alkaline pH of above 7, preferably a pH of 8 to 12, to theaqueous solution or slurry may be employed in admixture with theabrasive. Such materials are known and abrasive compositions containingthe same are disclosed in US. Patent No. 2,625,514, issued January 13,1953. The alkaline materials are the water-soluble inorganic alkalinebuilder salts preferably, such as the alkali metal carbonates (e.g.sodium carbonate), the alkali metal phosphates (e.g. trisodiumphosphate, tetrasodium pyrophosphate, sodium tripolyphosphate), thealkali metal silicates (e.g. sodium metasilicate) and the alkali metalborates (e.g. sodium borate) Any suitable base such as sodium andpotassium hydroxide, and tetramethylammonium hydroxide may be employedalso. It is preferred to use the normally solid alkaline salts and basesbut, if desired, a normally liquid alkaline material may be employed bysuitable combination with a solid carrier such as by adsorption upondiatomaceous earth, bentonite or the like. The alkaline ingredient maybe used in any desired amount depending upon the specific ingredient,but there is used usually about /2 to about 25% and preferably about 1to 15% by weight. These alkaline ingredients are used generally in theform of particles of any suitable size. The particle size of thealkaline ingredient is not critical and may correspond to theapproximate particle size of the abrasive.

Any water-soluble acidic ingredient which will dissolve in the cleansingsolution to yield an acidic pH of below 7, preferably a pH from 2 to 7,to the slurry may be employed in the product. In general, it ispreferred to employ a normally solid acid or acid salt in particulateform. If desired, a normally liquid material may be employed by suitablecombination with a solid carrier in particulate form, such asdiatomaceous earth or bentonite. The particle size of the acidicmaterial is not critical and it may be employed in any suitable size asillustrated for the abrasive. Examples of suitable materials are theorganic acids such as tartaric acid, maleic acid, boric acid, glutamicacid, citric acid, acetic acid, oxalic acid, gluconic acid and itslactone, and the like. Suitable inorganic acids and acid salts such assulfamic and phosphoric acids and sodium bisulfate may be employed also.These materials enhance the removal of tarnish and oxidant stains,particularly from metallic surfaces such as copper, aluminum, steel andthe like during use of the product.

The acidic ingredient should be used in any amount sufi'icient toconvert the alkaline solution to an acidic solution, preferably to asolution having a pH from about 2 to 5, when the quantity of acid hasbeen dissolved or otherwise released in the cleansing solution. Ingeneral, it is preferred that the amount of acid be from about /2 to 25and preferably from about 1 to 15% by weight. If a mixture containingthe alkaline and acidic ingredients in powdered form are added to water,the two materials tend to neutralize one another such that the cleansingsolution will have either an alkaline or an acidic pH conditiondepending upon the proportion and strength of the different ingredients.In order to obtain successive action of a separate and distinct natureit has been found that.

it is necessary to defer or retard the rate of solubility of one ofthese essential ingredients, preferably of-the solid acid constituent.For example, this deferred acidification permits the user toutilizeinitially the alkaline properties of the product followed by' useof the'acidic properties of the product. Accordingly, the rate ofsoluticn of the acidic constituent is to be sufiicien-tly depressed topermit the alkaline builder on use to dissolve first. The acidicconstituent must then be present in stoichiometric excess over thealkaline ingredient so that when it is dissolved or released after apredetermined time the pH of the cleansing solution is reduced to thedesired acidic level.

The rate of solubility of the acidic constituent may be reduced in anysuitable manner. It is preferred to coat the normally solid acidparticles with a solution inhibitor such as a Water-dispersible coatingagent. The presence of such a film or coating upon the particles of theacid will inhibit and retard the solubility of the acid when thecomposition is admixed with water. The amount of the coating is notcritical and may vary from a monomolecular film to a coating of anyparticular size depending upon the specific coating agent, itswater-dispersibility and the particular time interval which is desiredbefore the change in the pH condition of the aqueous cleaning solution.Thus, the predetermined time interval may be controlled so as to be afew seconds up to any point desired in the use of the product such as upto about 30 minutes. It is preferred that the change in pH occur fromabout 15 seconds to 15 minutes after the product is slurried in Water.

Any suitable material may be used as the coating agent such as thehigher fatty alcohols, preferably having 12 to 18 carbon atoms (e.g.lauryl alcohol, coconut fatty alcohol, cetyl alcohol, stearyl alcohol),mineral oil, the higher fatty acid amide compounds, preferably having 12to 18 carbon atoms in the acyl radical (lauric acid and coconut acid andmyristic acid primary amides and the corresponding monoethanolamides,isopropanolamides and diethanolamides) and their ethylene oxide reactionproducts having up to about 5 moles of ethylene oxide; the higher fattyacids, preferably having 12 to 18 carbons also such as stearic acid,palmitic acid, tallow fatty acids and the like. Other coating materialsare the waxlike polymers of ethylene glycol such as Carbowax 1500, 2025and 4000, the soluble starches and dextrins and the like. Thesematerials may have highly limited solubility in water to extreme watersolubility but are effective to delay the solubility or release of theacid in the cleansing solution. The term water-dispersible coating agentor equivalent as used herein refers to agents of varying watersolubility or dispersibility but which have been found to be dispersedor dissolved under conditions of use of the product. For example,organic materials such as lauryl alcohol and lauric acid amides andalkylolamides have limited water solubility but in the presence oforganic detergent material tend to dissolve in the cleansing solution.

The coating agent may be applied to the particles of the acid in anysuitable manner. It is preferred that the coating agent be dissolved,suspended or dispersed in an appropriate solvent or heated to moltenform and then sprayed or atomized on the individual acid particles toform the desired coating. Any suitable solvent may be employed, such asa normally gaseous propellant in a pressure container. Examples are thenormally gaseous low-molecular weight hydrocarbon and halogenatedhydrocarbon propellants, such as propane, butane, halogenated ethanesand methanes. The propellants known as the Freons and Genetrons aresuitable, examples being dichlorodifluoromethane andmonochlorodifluoroethane. Other solvents or dispersing mediums such asethanol, isopropanol and aqueous alcoholic mixtures may be suitablyemployed also. In this manner there may be obtained complete orincomplete coating or film on the surface of the acid particles asdesired. Where the coating agent is normally solid, it will dry to afilm, and where it is normally liquid it will be adsorbed or absorbedupon the surfaces of the particles. The coating material may be appliedalso in solid form to the surfaces of the acid particles by mixing thecoating agent in powdered form with the acid particles by suitable meansfor 22 carbon atoms.

mechanical admixture including tumbling in a rotary drum. When the finalcomposition is slurried in water to form an aqueous slurry or solution,the Water-soluble alkaline ingredient dissolves to form an alkalinesolution. Since the acid particles are coated with lauryl alcohol or anyother suitable coating as indicated, its rate of solution issufliciently depressed to permit the alkaline builder to dissolve first.After a predetermined time, which may be controlled as desired byselection of the particular coating agent, the coating materialdisperses in the aqueous medium whereupon the acid is released anddissolves so that the pH is reduced to the desired acidic condition.

As indicated, the alkaline ingredient may be coated in the mannerdescribed above so that uncoated acid particles are permitted to ionizeor dissolve initially forming an acidic condition followed by release ofthe alkaline ingredient after the coating has been removed sufficiently.

A more specific feature of this invention is that an organicsurface-active detersive agent be present in the composition. Suchorganic detersive agents may be either anionic, cationic or non-ionicagents as described in US. Patent No. 2,625,514. Examples of suitableanionic detergents are the water-soluble soaps and sulfated andsulfonated synthetic detergents. More particularly, it is preferred toemploy an alkyl benzene sulfonate detergent wherein the alkyl group hasabout 8 to 16 carbon atoms. Suitable examples are sodium decyl benzenesulfonate, sodium dodecyl and pentadecyl sulfonates wherein the dodecyland pentadecyl groups are derived from a propylene polymer, and sodiumkeryl benzene sulfonate. Other suitable agents are the surface-activesulfated or sulfonated aliphatic compounds, preferably having 8 toExamples thereof are sulfuric acid esters of polyhydric alcoholsincompletely esterified with higher fatty acids (e.g. coconut oilmonoglyceride monosulfate), the long-chain pure or mixed higher alkylsulfates (e.g. lauryl sulfate, coconut fatty alcohol sulfate), thehigher fatty acid ethanolamide sulfates; the higher fatty acid amides ofamino alkyl sulfonic acids (e.g. lauric acid amide of taurine), thehigher fatty acid esters of isethionic acid and the like.

Suitable cationic detergents which may be employed are the long-chainalkyl quaternary ammonium compounds (e.g. cetyl quaternary ammoniumsalts). Suitable examples are cetyl trimethyl ammonium chloride, cetylpyridinium chloride, and the like.

Various non-ionic agents may be employed also, such as the non-ionicpolyalkylene oxide condensates with an aliphatic or aromatic hydrophobicgroup. Such agents have about 5 to 50 alkylene oxide groups usually.Examples are the polyethylene oxide condensate with alkyl phenols having8 to 20 carbons in the alkyl group such as Igepal CA and CO, thepolyethylene oxide esters with higher fatty acids such as tall oil orlauric acid condensed with about 16 or 20 ethylene oxide groups, thepolyethylene oxide condensates with higher aliphatic alcohols such aslauryl, myristyl, oleyl or stearyl alcohol with 6 to 30 moles ethyleneoxide, and the like.

The anionic and cationic surface-active agents are used commonly in theform of Water-soluble salts. For the anionic compounds the alkali metaland ammonium salts are preferred whereas for the cationic agents thechloride, sulfate and acetate and the like acid salts are employedcommonly.

Any amount of the detersive compound may be employed which does notsubstantially adversely affect the desired characteristics of theproduct. In general, it is preferred that the detergent be present inamounts from about /2 to about 15% by weight and preferably from 1 to10% by weight. It is'preferred to employ the anionic and non-ionicsurface-active agents in a form where these materials have been premixedwith the alkaline builder salts. The mixture containing the detergentand alkaline salts in the form of anaqueous slurry may be subjected tothe usual drying procedures in order to obtain a relatively dryhomogeneous product such as by drum drying or spray drying of themixture in known manner.

The abrasive material, alkaline and acidic ingredients containing acoating upon one of the latter two materials are mixed in particulateform to produce a dry, cleansing powder. The ingredients are admixedmechanically by tumbling, fluidizing or the like in conventional soappowder mixers known in the art or by any other suitable means formechanical admixture.

It is a further feature of the present invention that the product maycontain a bleaching agent which results in effective bleaching actionduring use of the product. The bleaching agent may be incorporated intothe product in any suitable manner, such as during or after the mixingof the essential ingredients. In general, bleaching agents are moreetfective in one pH condition than another. Since the product during usewill form both acid and alkaline solutions, there will be obtained atsome stage optimum conditions for a particular bleaching agent. Ifdesired, the bleaching agent may be coated with any suitable materialsuch as the coating agents previously described so that the bleachingagent is released in the same manner. Examples of suitable bleachingagents are the known oxygen and chlorine-releasing substances, such assodium perborate, sodium, calcium and lithium hypochlorites,dichlorocyanuric acid, trichlorocyanuric acid, Chloramine T,dichlorodimethyl hydantoin and the like. The amount of bleaching agentis not critical but will be usually from about 0.01 to 25% of theproduct.

There may be incorporated in the product a suitable color indicatorwhich would demonstrate to the consumer when the change from one pHcondition to the other pH condition occurs or when a particular pH levelis obtained during use. The quantity of indicator is not critical'exceptthat it should be capable of producing a detectable coloration to thecleansing solution. In general, the amount of color indicator will varywith thetype of indicator but is usually from about 5 parts per millionto 3% of the product. If methyl orange is employed, the color of theslurry initially is yellow when the acid is coated, but when the aciddissolves subsequently the cleansing solution turns red. Anothersuitable color indicator is bromo thymol blue which changes color fromblue to yellow on conversion of the cleansing solution from an alkalineto an acid nature. The color indicator may be incorporated in anysuitable manner such as by spraying it directly upon the particles atany suitable stage in the mixing operation. If the indicator is solid itmay be dissolved or'dispersedin a suitable aqueous or alcoholic solutionin order to form a liquid solution for ease of application to theparticles. When the indicator solution driesupon-the particles theparticles will then have a coating of dye which dissolves or dispersesupon the initial admixture of the product with water. able dyes arephenol red, t-hymol blue, metacresol purple, etc. a a a 7 Various knownmaterialsmay be incorporated in the product also as desired.- Suitableexamples are minor amounts of anti-caking agents such as hydratedmagnesium trisilicate, sodium carboxymethyl-cellulose, perfume,antiseptics, germicides, skin emollient materials and thelike. 1

The following'examples are illustrative of the present invention and itwill be understood that the invention is not limited thereto. Allproportions indicated are by weight unless otherwise specified.

Example I --A powdered sulfamic acid is pretreated to apply a coating tothe particles as follows: 200 parts of the powdered sulfamic acid aretumbled in a Mason jar. Through an opening in the cover of the jar, aspray of a lauryl alcohol solution is introduced until 1 part of thelauryl alcohol has been deposited on the surface of the sulfamic acidpowder. The spraying composition conther suittains 30% lauryl alcoholdissolved in 70% of a 1:1 mixture of Freon-11 and 12 in a pressureresistant container.

An abrasive alkaline scouring cleanser is prepared by tumbling about 89parts of silex particles, about 0.5 parts of sodium per-borate powderand about 10.5 parts of an alkaline detergent material. This alkalinedetergent material is a spray-dried product containing about 30% sodiumdodecyl benzene sulfonate detergent, about 40% sodium tripolyphosphate,with the balance being primarily sodium sulfate. During this mixingoperation, about 5 drops of methyl orange indicator are added slowly toobtain good distribution. About 6 parts of the coated sulfamic acidparticles are added and the agitation is continued until the product isa uniform, homogeneous mixture.

When one volume of this composition is added to two volumes of waterwith mild agitation the resulting slurry turns a yellow color indicatingthat the product gives an alkaline reaction initially. After 2 minutesand 25 seconds the cleansing solution and the slurried produce change toa red color indicating an acidic reaction. The

composition shows effective cleansing and bleaching properties duringuse.

In comparison a'product prepared in similar manner except that uncoate'dpowdered sulfamate acid particles are admixed withthe alkaline scouringcleanser does not yield equivalent results. When the product is added towater with mild agitation, the color turns red immediately indicatingthat the product did not give an alkaline reaction at any time.

' Example II The procedure of Example I is repeated except that thelauric acid amide is applied similarly to the alkaline detergentparticles and not to the sulfamic acid. The ingredients are mixedthereafter in the same manner and the resulting product exhibitsinitially an acidic reaction in Water followed by an alkaline reaction.

7 Example 111 The procedure of Example I is repeated using 240 parts ofpowdered sodium bisulfate in place of the 200 parts of sulfamic acidwith similar results.

Example 1V Following the procedure of all of the above examples,

the 'followingcoating materials are employed in place of the laurylalcohol in Example I and the lauric acid amide in Example II withequivalent results: coconut fatty acid diethanolamide, lauric andstearic monoethanolamide, cetyl alcohol, tearyl alcohol, Carbowax 1500and 4000 and commercial stearic acid. Although the present invention hasbeen described with reference to particular embodiments and examples, itwill be apparent to those skilled in the art that variations andmodifications of this invention can be made and that equivalents can besubstituted therefor without departing from the principles and truespirit of the invention. I

What is claimed is:

1. An abrasive cleaning composition Whichfupon admixture with Water isadapted to yield an alkaline pH condition and an acidic pHcondition tothe resulting cleaning solution in a predetermined order of successionwhich comprises a mixture of a major proportion of awater-insolublesiliceous abrasive material, about /2 to 25% by weight ofa water-soluble alkaline inorganic builder salt which upon contact withwater renders the solution alkaline, about /2 to 25% by weight of awatersoluble normally solid acid which upon contact with water rendersthe solution acidic, one of the two latter ingredients dissolvingsufficiently upon admixture of said composition with water so that theresulting cleansing solution initially has one of said pH conditions andthe i 7 material resulting in a retarded rate of solubility so that itis not sufficiently soluble in said solution initially but subsequentlydissolves in said solution to convert it to the other of said pHconditions.

2. An abrasive cleaning composition which upon admixture with water isadapted to yield an alkaline pH condition and an acidic pH condition tothe resulting cleaning solution in a predetermined order of successionwhich comprises a mixture a major proportion of a water-insolublesiliceous abrasive material, a minor proportion from about /2 to 25% byWeight of a watersoluble alkaline ingredient which upon contact withwater renders the solution alkaline, and a minor proportion from about/2 to 25% by weight of a Water-soluble acidic ingredient which uponcontact with water renders the solution acidic, one of the two latteringredients dissolving sufliciently upon admixture of said compositionwith water so that the resulting cleaning solution initially has one ofsaid pH conditions and the other ingredient having a coating of awater-dispersible material to retard its initial solubility but beingpresent in a stoichiometric excess so that it subsequently converts saidcleaning solution to the other of said pH conditions.

3. An abrasive cleaning composition in accordance with claim 2 whereinsaid acid is sulfamic acid.

4. An abrasive cleaning composition in accordance with claim 2 whereinsaid coating is a higher fatty alcohol.

5. An abrasive cleaning composition in accordance with claim 2 whichcontains about /2 to 15% by weight of a water-soluble organic detergent.

6. An abrasive cleaning composition in accordance with claim 2 whichcontains about /2 to 25% by Weight of a bleaching agent.

7. An abrasive cleaning composition in accordance with claim 2 whichcontains a color indicator whereby said composition upon admixture withwater results in diiTerently colored solutions in said alkaline andacidic pH conditions.

8. An abrasive cleaning composition which upon admixture with water isadapted to yield an alkaline pH condition and an acidic pH conditionsuccessively to the resulting cleaning solution which comprises amixture of a major proportion of a water-insoluble siliceous abrasivematerial, about /2 to 25% by weight of a water-soluble inorganicphosphate salt which upon contact with water renders it alkaline, about/2 to 25% by weight of a watersoluble normally solid acid which uponcontact with water renders it acidic, said acid having a coating of awater-dispersible material and said composition upon admixture withwater yielding an alkaline pH condition in water which is subsequentlyconverted to an acidic pH condition.

9. An abrasive cleaning composition in accordance with claim 8 whichcontains particles of sulfamic acid coated with said material.

10. An abrasive cleaning composition in accordance with claim 8 whichcontains about A: to 25 by weight of sodium perborate.

11. An abrasive cleaning composition in accordance with claim 8 whichcontains a color indicator to indicate by color change when the cleaningsolution is converted from said alkaline to said acidic pH condition.

12. An abrasive cleaning composition which upon admixture with water isadapted to yield an alkaline pH condition and an acidic pH conditionsuccessively to the resulting cleaning solution which comprises amixture of a major proportion of a water-insoluble siliceous abrasivematerial, about /2 to 25 of a water-soluble inorganic alkaline buildersalt which upon contact with the water renders the solution alkaline,about /i to 25% by weight of water-soluble normally solid acid whichupon contact with the water renders it acidic, said acid having acoating of a water-dispersible material to retard its rate ofsolubility, but being present in stoichiometric excess so that saidcomposition upon admixture with water yields an alkaline pH conditioninitially which is subsequently converted to an acidic pH condition.

13. A method of preparing an abrasive cleaning composition characterizedby a mixture of a major proportion of a water-insoluble siliceousabrasive material, a minor proportion from about /2 to 25% by weight ofa water-soluble alkaline compound and a minor proportion from about /2to 25% by Weight of a water-soluble acidic compound which upon admixturewith water is adapted to yield an alkaline pH condition and an acidic pHcondition to the resulting cleaning solution in a predetermined order ofsuccession which comprises coating with a water-dispersible compound oneof the latter two ingredients to retard its rate of solubility in water,and admixing the resulting coated compound in an amount instoichiometric excess with the other ingredient and with said abrasiveto form a uniform mixture.

14. A method of preparing an abrasive cleaning composition characterizedby a mixture of a major proportion of water-insoluble siliceous abrasivematerial, and minor proportions of about /2 to 25% by weight each of awater-soluble alkaline ingredient and a water-soluble acidic ingredientadapted to yield an alkaline pH condition and an acidic pH conditionsuccessively upon admixture With water which comprises treating saidacidic ingredient to apply a coating of a Water-dispersible material,and admixing the coated acidic material with said abrasive and alkalinematerial to 'form a homogeneous mixture.

15. A method in accordance with claim 14 wherein said acidic ingredientis a normally solid water-soluble acid.

16. A method in accordance with claim 14 which comprises admixing acolor indicator with said mixture to indicate by color change when theresulting cleaning solution is converted from said alkaline to saidacidic pH condition.

References Cited in the file of this patent UNITED STATES PATENTS284,494 Michaelis Sept. 4, 1883 856,672 Best et al. June 11, 1907871,612 Nesfield Nov. 19, 1907 980,936 Federer Jan. 10, 1911 1,075,663Meerbott Oct. 14, 1913 1,854,235 Stoddard Apr. 19, 1932 1,966,203Gravell July 10, 1934 1,989,765 Moss et a1. Feb. 5, 1935 2,034,361Sutton Mar. 17, 1936 2,196,901 Ham et a1. Apr. 9, 1940 2,228,483 RaekeJan. 14, 1941 2,308,992 Mertens Jan. 19, 1943 2,430,233 Magill Nov. 4,1947 2,497,057 Pape et a1 Feb. 7, 1950 2,498,344 Rider et a1. Feb. 21,1950 2,540,253 Gakenheimer Feb. 6, 1951 2,578,270 Strain Dec. 11, 19512,589,108 Mark Mar. 11, 1952 2,625,514 Kirschenbauer Ian. 13, 19532,763,618 Hendrix Sept. 18, 1956 FOREIGN PATENTS 749,857 Great BritainJune 6, 1956

1. AN ABRASIVE CLEANING COMPOSITION WHICH UPON ADMIXTURE WITH WATER ISADAPTED TO YEILD AN ALKALINE PH CONDITION AND AN ACIDIC PH CONDITION TOTHE RESULTING CLEANING SOLUTION IN A PREDETERMINED ORDER OF SUCCESSIONWHICH COMPRISES A MIXTURE OF A MAJOR PROPORTION OF A WATER-INSOLUBLESILICEOUS ABRASIVE MATERIAL, ABOUT 1/2 TO 25% BY WEIGHT OF AWATER-SOLUBLE ALKALINE INORGANIC BUILDER SALT WHICH UPON CONTACT WITHWATER RENDERS THE SOLUTION ALKALINE, ABOUT 1/2 TO 25% BY WEIGHT OF AWATERSOLUBLE NORMALLY SOLID ACID WHICH UPON CONTACT WITH WATER RENDERSTHE SOLUTION ACIDIC, ONE OF THE TWO LATTER INGREDIENTS DISSOLVINGSUFFICIENTLY UPON ADMIXTURE OF SAID COMPOSITION WITH WATER SO THAT THERESULTING CLEANSING SOLUTION INTIALLY HAS ONE OF SAID PH CONDITIONS ANDTHE OTHER INGERDIENT HAVING A COATING OF WATER-DISPERSIBLE MATERIALRESULTING IN A RETARDED RATE OF SOLUBILITY SO THAT IT IS NOTSUFFICIENTLY SOLUBLE IN SAID SOLUTION INITIALLY BUT SUBSEQUENTLYDISSOLVES IN SAID SOLUTION TO CONVERT IT TO BE OTHER OF SAID PHCONDITIONS.